Scanning-based EMMI detection system and detection method thereof
By adopting a combination of scanning units and single-point detectors in EMMI technology, combined with spatial filtering system and confocal technology, the problem of poor imaging quality of existing EMMI technology is solved, and high sensitivity detection and accuracy of micro defects of semiconductor devices is achieved. position.
Patent Information
- Application Number
- CN202411574383.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-01-07
AI Technical Summary
The existing EMMI technology has poor imaging quality and is difficult to detect minor defects in semiconductor devices. This is mainly because the plane array cameras are difficult to achieve high-sensitivity optical signal detection, resulting in noise signals covering up useful optical signals.
Using a scanning-based EMMI detection system, point-by-point scanning and electrical signal detection are performed through the scanning unit and single-point detector in the optical transmission module. Combined with spatial filtering system and confocal technology, the imaging effect is optimized, the signal-to-noise ratio and the clearness of optical signals are improved. Spend.
High-sensitivity signal detection for semiconductor devices is realized, imaging quality is improved, defect location can be accurately positioned, and detection ability of micro defects is enhanced.
Smart Images
Figure CN119269532A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor detection technology, and in particular to a scanning-based EMMI detection system and a detection method thereof. Background Art
[0002] During the manufacturing and use of semiconductor devices, their performance is often affected by tiny internal defects. To ensure product quality, these tiny defects need to be accurately detected. EMMI (also called PEM, Photon Emission Microscope, light emission microscope, micro-light microscope) is a common technology for semiconductor defect detection. This technology locates the defect position by capturing the weak light signal (mainly the composite luminescence of thermally excited electron-hole pairs) when the device is working.
[0003] However, existing EMMI technologies generally use area array cameras for image acquisition, which makes it difficult to achieve high-sensitivity light signal detection. As a result, noise signals may mask useful light signals, resulting in a decrease in image quality, making it difficult to detect tiny defects in semiconductor devices. Summary of the invention
[0004] In view of the above situation, the present invention provides a scanning-based EMMI detection system and detection method thereof to solve the problem that the existing EMMI technology has poor imaging quality and is difficult to detect tiny defects of semiconductor devices.
[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a scanning-based EMMI detection system, which includes: a sample stage for carrying a sample; a light source for generating a laser and irradiating the sample to generate reflected light; an optical transmission module for receiving and transmitting the laser to the sample, arranged between the light source and the sample stage; a power source for powering the sample and exciting the sample to generate emitted light, the power source being connected to the sample; a single-point detector for receiving the reflected light and the emitted light and converting them into electrical signals, the reflected light and the emitted light being both transmitted back to the single-point detector through the optical transmission module; and a computing system for processing the electrical signal into an image, the computing system being connected to the single-point detector.
[0006] Preferably, the optical transmission module includes a beam splitter for passing the laser and reflecting the reflected light and the emitted light, a scanning unit for receiving the laser and scanning, and an objective lens for receiving the scanned light and transmitting it to the sample, and the scanning unit includes a pair of x-axis galvanometers and y-axis galvanometers that can change the direction of the laser.
[0007] Preferably, the optical transmission module further comprises a dual telecentric relay system disposed between the scanning unit and the objective lens, the dual telecentric relay system comprising a scanning lens for receiving and focusing the scanning light, and a sleeve lens for receiving and transmitting the focused light to the objective lens.
[0008] Preferably, the optical transmission module further comprises a reflector for changing the direction of optical transmission, and the reflector is arranged between the dual telecentric relay system and the objective lens, and between the beam splitter and the single point detector. The dual telecentric relay system can perform field curvature correction, distortion compensation, and collimation on the scanning light to optimize the imaging effect.
[0009] Preferably, it further comprises a spatial filtering system disposed between the single-point detector and the optical transmission module, wherein the spatial filtering system comprises two lenses and a spatial pinhole structure disposed between the two lenses.
[0010] Preferably, the single-point detector is a single-photon detector, an avalanche photodetector or a balanced photodetector.
[0011] The present invention provides a detection method using a scanning-based EMMI detection system, comprising the following steps:
[0012] Turning on the light source to generate laser light, the laser light is transmitted to the sample through the optical transmission module, the sample is irradiated by the laser light and generates reflected light, the reflected light is then transmitted back to the single-point detector through the optical transmission module, the single-point detector receives the reflected light and converts it into a first electrical signal, and the computing system processes the first electrical signal to form a pattern diagram;
[0013] Determine the sample detection position according to the pattern diagram and adjust the sample position;
[0014] Turn off the light source and turn on the power source, the power source supplies power to the sample and excites the sample to generate emission light, the emission light is reversely transmitted to the single point detector through the light transmission module, the single point detector receives the emission light and converts it into a second electrical signal, and the computing system processes the second electrical signal to form a scanning emission photon map;
[0015] The computing system performs image superposition processing on the pattern image and the scanning emission photon image to obtain the morphology and defect position of the sample.
[0016] The beneficial effect of the present invention is that a scanning-based EMMI detection system and detection method of the present invention electrically excites the sample to generate an emission signal through a power source, uses a single-point detector for detection, and cooperates with a precisely controlled scanning unit to scan the sample point by point, records the intensity of the emitted light signal, and realizes high-sensitivity signal detection of the emitted light, improves the signal-to-noise ratio, and thus improves the imaging quality. At the same time, a spatial filtering system is set up to realize the combination of confocal technology, which can further suppress background noise and enhance the clarity of the light signal. The present invention combines the pattern diagram with the scanning electronic imaging diagram to establish a two-dimensional and three-dimensional luminescence distribution diagram of the entire measured surface, thereby realizing accurate positioning of the defect position. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0018] Figure 1 It is a schematic diagram of the overall structure of the scanning-based EMMI detection system of the present invention.
[0019] The corresponding relationship between the reference numerals and the components is as follows:
[0020] 1. Light source; 2. Beam splitter; 3. Scanning unit; 31. X-axis galvanometer; 32. Y-axis galvanometer; 4. Dual telecentric relay system; 41. Scanning lens; 42. Sleeve lens; 5. Reflector; 6. Objective lens; 7. Sample; 8. Sample stage; 9. Power source; 10. Spatial filtering system; 101. Lens; 102. Spatial pinhole structure; 11. Single point detector; 12. Computing system. DETAILED DESCRIPTION
[0021] To facilitate understanding of the present invention, the following description is provided in conjunction with the accompanying drawings and embodiments.
[0022] See also Figure 1 The present invention provides a scanning-based EMMI detection system, comprising a sample stage 8, a light source 1, an optical transmission module, a power source 9, a single-point detector 11, and a computing system 12. Among them:
[0023] The sample stage 8 may be a moving stage for carrying the sample 7 and moving to adjust the position of the sample 7. The light source 1 is used to generate laser light and illuminate the sample 7 to generate reflected light. The optical transmission module is disposed between the light source 1 and the sample stage 8, and is used to receive and transmit the laser light to the sample 7. The power source 9 is connected to the sample 7, and is used to power the sample 7 and excite the sample 7 to generate emitted light. The single-point detector 11 is used to receive the reflected light and the emitted light and convert them into electrical signals. Both the reflected light and the emitted light are transmitted back to the single-point detector 11 through the optical transmission module. The computing system 12 is connected to the single-point detector 11, and is used to process the electrical signal into an image.
[0024] Specifically, the pattern image is firstly performed, and the light source 1 is turned on. The light source 1 provides the illumination beam required for the pattern image. According to the characteristics of the sample 7 to be measured, a laser of any wavelength band can be selected. The laser is transmitted to the sample 7 through the optical transmission module. The sample 7 generates reflected light after being irradiated by the laser. The reflected light is then transmitted back to the single-point detector 11 through the optical transmission module. The single-point detector 11 converts the reflected light signal into an electrical signal. The computing system 12 processes the electrical signal to form a pattern image. The sample stage 8 is adjusted according to the pattern image until the position to be detected of the sample 7 is found. Then, scanning emission photon imaging is performed, that is, the light source 1 is turned off, and the power source 9 is turned on to electrically excite the sample 7, so that the sample 7 is excited to generate emission light. The emission light is transmitted to the single-point detector 11 through the optical transmission module. The single-point detector 11 converts the emission light signal into an electrical signal. The computing system 12 processes the electrical signal to form a scanning emission photon image. Finally, the scanning emission photon image and the pattern image are subjected to image superposition processing to obtain the morphology and defect position of the sample 7.
[0025] When scanning the emitted photon imaging, the sample 7 can be electrically excited to realize non-contact detection of the sample 7, and the electrical excitation can enhance the luminescence intensity of the sample 7, thereby improving the signal-to-noise ratio of the detector. The single-point detector 11 can detect very weak light signals, even single photons, and has high sensitivity. Since it only detects the light signal of one point, it can provide very high spatial resolution. Therefore, the single-point detector 11 can realize high-sensitivity signal detection of the emitted light generated by the electrically excited sample 7, thereby improving the imaging quality and making semiconductor defect detection more sensitive, accurate and stable.
[0026] As a preferred embodiment, the optical transmission module includes a beam splitter 2 for passing laser and reflecting reflected light and emitted light, a scanning unit 3 for receiving laser and scanning, and an objective lens 6 for receiving the scanned light and transmitting it to the sample 7. The scanning unit 3 includes a pair of x-axis galvanometers 31 and y-axis galvanometers 32 that can change the direction of the laser. The x-axis galvanometer 31 and the y-axis galvanometer 32 can scan along the x-axis and the y-axis respectively, and the reflection angle of the galvanometer can be changed to realize arbitrary deflection of the laser.
[0027] Since the beam splitter 2 can pass the laser and reflect the reflected light and the emitted light, a light incident loop and a light reflection loop can be formed under the action of the beam splitter 2. Specifically, in the process of pattern imaging, the laser passes through the beam splitter 2 and part of the laser passes through the beam splitter 2, and part of the laser is then transmitted to the sample 7 through the scanning unit 3 and the objective lens 6 in sequence to form a light incident loop, and the reflected light of the sample 7 is then transmitted to the single point detector 11 through the objective lens 6, the scanning unit 3, and the beam splitter 2 in sequence to form a light reflection loop. In the process of scanning emission photon imaging, the emitted light of the sample 7 can be directly transmitted to the single point detector 11 through the light reflection loop.
[0028] As a preferred embodiment, the optical transmission module also includes a dual telecentric relay system 4 arranged between the scanning unit 3 and the objective lens 6, and the dual telecentric relay system includes a scanning lens 41 for receiving and focusing the scanning light, and a sleeve lens 42 for receiving and transmitting the focused light to the objective lens 6.
[0029] As a preferred embodiment, the optical transmission module further includes a reflector 5 for changing the direction of optical transmission, and the reflector 5 is disposed between the dual telecentric relay system 4 and the objective lens 6, and between the beam splitter 2 and the single point detector 11. The reflector 5 only serves to adjust the direction of the light beam, and can be omitted or added according to the test conditions.
[0030] As a preferred embodiment, it also includes a spatial filtering system 10 disposed between the single-point detector 11 and the optical transmission module, and the spatial filtering system 10 includes two lenses 101 and a spatial pinhole structure 102 disposed between the two lenses 101. The spatial pinhole structure 102 can be the aperture of the optical fiber. The spatial filtering system 10 ensures that only the light signal from the focal plane is detected, enhances the spatial resolution and improves the signal-to-noise ratio, realizes the combination of EMMI technology and confocal, and thus realizes optical sectioning, three-dimensional stereo imaging, etc. With the optical sectioning capability of confocal, by changing the Z-axis position of the sample 7 and scanning multiple two-dimensional images for superposition, a three-dimensional image can be obtained.
[0031] As a preferred implementation, the single-point detector 11 is a single-photon detector, an avalanche photodetector or a balanced photodetector.
[0032] The present invention provides a detection method using a scanning-based EMMI detection system, comprising the following steps:
[0033] The light source 1 is turned on to generate laser light, which is transmitted to the sample 7 through the optical transmission module. The sample 7 is irradiated by the laser light and generates reflected light, which is then transmitted back to the single-point detector 11 through the optical transmission module. The single-point detector 11 receives the reflected light and converts it into a first electrical signal. The computing system 12 processes the first electrical signal to form a pattern diagram.
[0034] Determine the detection position of sample 7 according to the pattern diagram and adjust the position of sample 7;
[0035] Turn off the light source 1, turn on the power source 9, the power source 9 supplies power to the sample 7 and excites the sample 7 to generate emission light, the emission light is transmitted back to the single point detector 11 through the optical transmission module, the single point detector 11 receives the emission light and converts it into a second electrical signal, and the computing system 12 processes the second electrical signal to form a scanning emission photon map;
[0036] The computing system 12 performs image superposition processing on the pattern image and the scanning emission photon image to obtain the morphology and defect positions of the sample 7.
[0037] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A scanning-based EMMI detection system, characterized in that: include: A sample stage for holding a sample; A light source for generating laser light and irradiating the sample to generate reflected light; An optical transmission module for receiving and transmitting the laser to the sample, disposed between the light source and the sample stage; A power source for supplying power to the sample and exciting the sample to generate emitted light, the power source being connected to the sample; A single-point detector for receiving the reflected light and the emitted light and converting them into electrical signals, wherein the reflected light and the emitted light are both reversely transmitted to the single-point detector through the optical transmission module; A computing system for processing the electrical signal into an image, wherein the computing system is connected to the single point detector.
2. The scanning-based EMMI detection system according to claim 1, characterized in that: The optical transmission module includes a beam splitter for passing the laser and reflecting the reflected light and the emitted light, a scanning unit for receiving the laser and scanning, and an objective lens for receiving the scanned light and transmitting it to the sample. The scanning unit includes a pair of x-axis galvanometers and y-axis galvanometers that can change the direction of the laser.
3. The scanning-based EMMI detection system according to claim 2, characterized in that: The optical transmission module further comprises a dual telecentric relay system disposed between the scanning unit and the objective lens, wherein the dual telecentric relay system comprises a scanning lens for receiving and focusing the scanning light and a sleeve lens for receiving and transmitting the focused light to the objective lens.
4. The scanning-based EMMI detection system according to claim 2, characterized in that: The optical transmission module also includes a reflector for changing the direction of light transmission, and the reflector is arranged between the dual telecentric relay system and the objective lens, and between the beam splitter and the single point detector.
5. The scanning-based EMMI detection system according to claim 1, characterized in that: It also includes a spatial filtering system arranged between the single-point detector and the optical transmission module, and the spatial filtering system includes two lenses and a spatial pinhole structure arranged between the two lenses.
6. The scanning-based EMMI detection system according to claim 1, characterized in that: The single-point detector is a single-photon detector, an avalanche photodetector or a balanced photodetector.
7. A detection method of the scanning-based EMMI detection system according to claim 1, characterized in that: The steps include: Turning on the light source to generate laser light, the laser light is transmitted to the sample through the optical transmission module, the sample is irradiated by the laser light and generates reflected light, the reflected light is then transmitted back to the single-point detector through the optical transmission module, the single-point detector receives the reflected light and converts it into a first electrical signal, and the computing system processes the first electrical signal to form a pattern diagram; Determine the sample detection position according to the pattern diagram and adjust the sample position; Turn off the light source and turn on the power source, the power source supplies power to the sample and excites the sample to generate emission light, the emission light is reversely transmitted to the single point detector through the light transmission module, the single point detector receives the emission light and converts it into a second electrical signal, and the computing system processes the second electrical signal to form a scanning emission photon map; The computing system performs image superposition processing on the pattern image and the scanning emission photon image to obtain the morphology and defect position of the sample.